This focused review includes two parts. In the first part, the previous studies on the deformations of monocrystalline Si induced by nanoscratching were summarised. In the second part, our recent studies on the scratching-induced deformation of Si were systematically presented. The studies have demonstrated that lateral force in nanoscratching plays a key role in the amorphisation and phase transformation of Si under mechanical loading. The deformation route of Si appears to be different from those reported from the nanoindentation studies.